The simplest music playing app, PurePlay works with iTunes Document Sharing to allow you to drag and drop music from your computer onto your iPhone.
Its easy to use with a concise set of features.
PLEASE NOTE that unless you use Document Sharing, you wont see any songs in PurePlay. For instructions on Document Sharing please see here:
https://support.apple.com/en-gb/HT201301
PurePlay doesnt: integrate with the iTunes library
PurePlay doesnt: do anything with the cloud
PurePlay doesnt: need you to sign up or sign in